1. Field of the Invention
The present invention relates to a device which properly displays map data in cooperation with, for example, a geographic information system, and relates, in particular, to a map display device, a map display system, and a map display method which handle raster layers corresponding to a layer structure.
2. Description of the Related Art
Currently, usually, map data is transmitted from a server to a client terminal, and is displayed on the client terminal. For example, when the map data is transmitted and received via the Internet, the map data is analyzed using a browser or the like, and displayed on a screen at the client terminal. Here, the map data generally includes raster data and vector data. Raster data is image data producing a map with many small dots, and vector data is data producing a map with line segments and graphics. When the map data is retained in the server provided in a network environment, it is often managed in the form of vector data for convenience of information retrieval and update processing.
However, when the map data is managed in the form of the vector data in the network environment as in the prior art described above, separate application software needs to be used to handle the map data because the map data of separately developed geographic information systems have their own formats. In addition, due to the different formats of map data, it is difficult to process and edit the map data or the like of different geographic information systems and display the map data correctly.